Esters of alpha-acyloxyacrylic acids



Patented Mar. 7, 1950 UNITED STATES PATENT OFFICE 2,499,393- ESTERS or u-ACYLOXYACRYLIC Acms William 0. Kenyon, Cornelius C. Unru'h, and Thomas T. M. Laakso, Rochester, N. Y.', as-' signors to Eastman Kodak Company, Rochester; N. Y., a corporation of New Jersey No Drawing. Application September 25, 1947, Serial No. 776,154

8 Claims.

pyruvate, however a reaction mixture which is. difiicult to separate into its component parts usually results. The products so prepared are obtained in low yields and are homopolymerized with extreme difficulty. In contradistinction thereto, the products prepared according to the process of the present invention are obtained in excellent yield and can be homopolymerized without difficulty.

It is, therefore, an object of our invention to provide a process for preparing esters of a-acylo'xyacrylic acids.

A further object of our invention is to provide a process for preparing esters of oc-tCYlOXYEtClYliC acids in increased yields and in condition suitable for polymerizing.

A still further object of our invention is to provide valuable new intermediates which can be used in the preparation of esters of a-acyloxyacrylic acids. Other objects will become apparent hereinafter from a consideration of the following description.

According to the process of our invention we react an ester of a 18-ha101actic acid with an acylating agent to produce an ester of an a-acyloxyp-halopropionic acid, which is then dehydrohalogenated by heating with an organic tertiary amine to produce the desired ester of an a-acyloxyacrylic acid.

The p-halolactic acids which we can use in our process can be represented by the formula:

tate, ethyl fi-chlorolactate, n-propyl p-chlorolac-' tate, isopropyl p-chlorolactate, n-butyl fi-chloro lactate, isobutyl fi-chlorolactate, benzyl fl chlorolactate, methyl p-brojmolactate, n-butyl fl-bromo lactate, etc. a

The acylating agents which we use are the anhydrides or acid halides of acids having the formula:

RCOOH wherein R represents a member selected from the group consisting of an alkyl group, such as methyl, ethyl, n-propyl, isopropyl (i. e. an alkyl group having the formula CnI-I2n+1 where n is a positive integer from 1 to 3) and an aryl group, such as phenyl, m-, and p-tolyl (i. e. a mononuclear aryl group of thebenzene series having 6 to '7 carbon atoms). Typical are: acetic anhydride, acetyl chloride, propionic anhydride,

propionyl chloride, n-butyric anhydride, isobutyric anhydride, n-butyryl chloride, isobutyryl chloride, benzoic anhydride, benzoyl chloride, etc. Other acylating agents, such as the ketenes (e. g. ketene, methyl ketene, etc.) can be used, although there is usually no advantage in using them.

After acylation of the fi-halolactate ester, the er-acyloXy-B-halopropionate ester can be separated irom the reaction mixture and then purified by distillation in a vacuum, if desired. Advantageously we can add an organic tertiary amine to the reaction mixture resulting from the acylation, and heat the mixture under reflux.

The tertiary amines which we can use are the aliphatic amines, such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, etc.; the aromatic amines, such as N,N-dimethylaniline, N,N-diethy1ani1ine, etc.; and the heterocyclic amines, such as pyridine, quinoline, etc.

The following equations will serve to show the mechanism of our process:

if XCHz-CH-COOR; RG-Y xoH2-oHc00R1+tei-tiar amine CH;;=OCOOR1 C-R CR g H wherein R, R1, and X have the above designated definition and Y stands for a halogen atom or a RCOO- group.

Since a number of the p-halolactates which We can use as starting materials are not described in the literature, the following examples will serve to illustrate the manner in which these substances can be prepared:

EXAMPLE I.METHYL fi-CHLOROLACTATE 1525 gms. (10 mols) of B-chlorolactic acid and 3050 grns. mols) of absolute methanol were placed in a glass vessel and 4% by weight of anhydrous hydrogen chloride added. The solution was then refluxed for 20 hours, at the end of which time the excess methanol was removed under vacuum, and the residue fractionally distilled. A yield of 505 gms. of methyl ,B-chlorolactate boiling at 80-805 C./ 9 was obtained. The melting point of the ester was found to be 182l C. Analysis was as follows:

7 Calculated Found EXAMPLE II.Is0BU'rYL fi-CHLOROLACTA'I? 996 gms. (8 mols) of fi-chlorolactic acid and 2000 gms. (27 mols) of isobutyl alcohol were placed in a glass vessel and 4% by weight of anhydrous hydrogen chloride passed in. The solution was then refluxed for 20 hours, and the excess isobutyl alcohol removed under K 191 1 2 The residue was then fractionally distilled, and isobutyl B-chlorolactate boiling at 75-77? 0/25 mm. was obtained. The distillate gradually solidified, and the melting point Was observed to be 2527 C; Analysis was as follows:

C culat d 9 EXAMPLE III.N-.BUTYL p-cHLoRoLAc'rA'rE 996 guns. (8 mols) of ,B-chlorolactic acid and 200 gms. (27 mols) of nbutanol were placed in. a, glass vessel and 4% by weight of dry hydrogen chloride gas passed in. The solution was then refluxed for 20 hours, and the excess.

n-butanol removed under vacuum. The residue Was fractionally distilled, and an 85% yield of n-butyl B-chlorolactate boiling at 118-119?- C/16 mm. was obtained. Analysis was as follows:

C at Fo nd The ethyl ester of p-chlorolactic acid was described by C. F. Koelsch in the Journal of the American Chemical Society,-- vol. 52 (1930), pages 1105-1106. Koelsch also described the preparation of B-chlorolactic acid, oxidizing glycerol chlorohydrin to the acid. By substituting molecularly equivalent amounts of other alcohols in the above example, other esters of p-chlorolactic acid can be prepared. For example, benzyl' alcohol can replace the methanol of Example I to produce benzyl ,B-chlorolactate having the formula:

Ol.CHzCHGOOCH C H In a similar manner n-propanol and isopropanol can replace the n-butanol or isobutanol of Examples 1 a II to eque Mhlomlaotiq acid esters of these alcohols.

The following examples demonstrate the meth-- od whereby we prepare our esters of o -acylqxy: acrylic acids.

EXAMPLE IV.METHYL oL-ACETOXYACRYLATE o HFC-C o o c H;

.(lJCHa Ac wmtmn.

The methyl a-chlorolactate produced in Example I (505 gms. or 3.63 mols) was added to l;-ll (l.-g ms. 1 0.89 mp1s) of acetic anhydride and the mixture boiled under reflux for 20 hours. Afterfractionation under vacuum, a 77% yield of methyl oc-ECE iJOZY-B-ChlOIOpX'OpiOIlELtB, boiling at 92.5 to 93.5 6/9 mm., was obtained. The analysis of the produced ester was as follows:

Calculated Found Dehydrochlorination 3.89. ems. 1- .3. m le? o th m h l e t firshlo op op e ate r r d. abo e 284 (.222'IH9:1) of uin ina and 1000. @Q- Q dry h enhsne-i iee benzen W 'est r q unde r fl o 9 h r Th b nzene w then ns ntr ted nd the. residual il. i aqti nat tl un r c m.

A i0% yield of methyl -acetoxyacrylate boiling a 4 C-/ s. obta ne The e e was then purified by dissolving in thiophenef ee-b nze e Wash n with iee ol 2% s u i acid, followedby washing with ice-cold waterand cold 2%, sodium carbonate solution, drying the benzene layer, and finally concentrating the benzene layer and fractionally distilling as before. The analysis was as f ollows; it

I Calculated Found D ehydrochlorz'nation 35o gIllS (1.29 mols) of ethyl a-acetoxyefie. ch lorgpropionate, prepared as above, 200 grns. (1.55 mols) ofzquinoline, and 1000 cc. of dry thiophepe-free benzene were stirred under re} fluxfor 20 hours. The benzene was then concentrated and the residual oil fractionated under vacuum. A 94% yield (191 gms.) of ethyl The reaction mixture was 7 Calculated Found a-acetoxyacrylate containing a trace of quinoline was obtained (B. P. 99-100 C./135 mm.). This ester was then dissolved in thiophene-free benzene and purified by washing with ice-cold 2% sulfuric acid, followed by washings with cold water and cold 2% sodium carbonate solution. After drying, the benzene layer was concentrated, and the residual oil fractionated under vacuum. The following analysis was found for the purified monomer:

Calculated Found EXAMPLE VI.ETHYL oL-BUTYROXYACRYLATE CH=C-C O C211:

*4]? C aH1 Acylation 715 gms. (5 mols) of ethyl fl-chlorolactate and 2070 gms. (13 mols) of n-butyric anhydride were heated on a steam bath for 20 hours. The reaction mixture was then fractionated under vacuum, and a cut, B. P. 113-114 C./7 mm., of ethyl a-butyroxy-fi-chlorolactate was obtained in 55.7% yield (620 gms. Analysis was as follows:

Calculated Found 48. so 49. 16 e. 74 6. s2 16. 60 16. 45

Dehydrochlorination 620 gms. (2.7 mols) of the ester prepared above, 403 gms. (3.2 mols) of quinoline, and 1000 cc. of dry thiophene-free benzene were stirred under reflux for 20 hours. The benzene was then concentrated, and the residual oil fractionated under vacuum. A 60% yield of ethyl a-butyroxyacrylate, B. P. 95-96 C./11 mm., was obtained having the following analysis.

Calculated Found 1250 gms. (6.96 mols) of isobutyl B-chlorolactate, prepared as above, and 2150 gms. (21 mols) of acetic anhydride were heated on a steam bath for 20 hours. The reaction mixture was then fractionated under vacuum and a 91% yield of isobutyl a-acetoxy-p-chloropropionate, B. P.

117-117.5/8 mm., was obtained. Analysis was as follows:

1425 gms. (6.4 mols) of the above ester, 1010 gms. (7.8 mols) of quinoline and 2000 cc. of dry thiophene-free benzene were heated under reflux for 20 hours. The benzene layer was concentrated, and the residual oil fractionated under vacuum. A 54.6% yield of isobutyl a-acetoxyacrylate, B. P. 110.5-111 C./22 mm., was obtained. This ester was further purified by dissolving in thiophene-free benzene, washing with ice-cold 2% sulfuric acid, followed by washings with cold water and cold sodium carbonate solution. The benzene layer was then dried, concentrated under vacuum, and finally fractionally distilled under vacuum to give a pure isobutyl a-acetoxyacrylate. Analysis was as follows:

Calculated Found- EXAMPLE VIII.-NBUTYL ot-ACETOXYACRYLATE O-(|J0Ha Acetylation Calculated Found 48. 55 49. 51 e. 74 a. 77 1s. 97 15. 03

Dehydrochlorination Analysis was as follows:

Calculated Found By substituting benzyl p-chlorolactate in a molecularly equivalent amount in the above example, benzyl a-acetoxyacrylate can be prepared.

' EXAMPLE IX.ETHYL oz-BENZOXYACRYLA'IE CHz=CCOOC2H5 t o--o.,n5

Benzoylation 762.5 gins. (5 mols) of ethyl B-chlorolactate and 702.8 gms. (5 mols) of benzoyl chloride were heated under reflux for.20'hours. The reaction mixture was fractionated and a 40% yield (520 gins.) of ethyl a-benzoxy-B-chloropropionate, B. "P. 133-18? C. /l5 mm., was obtained. The ester was cooler to 15 .C. but no crystals formed. Analysis was as follows:

Calculated Found 'Dehydrochlorinatzon Calculated Found C l 64. 90 64. 01 H 5. 40 5. 24

By substituting, a moleoularly equivalent amount of propionyl chloride in the above example, ethyl a-propionoxyacrylate can be prepared.

The esters prepared as described above can be homopolymerized or polymerized with another unsaturated compound with ease. The velocity of the polymerization can be accelerated to a considerable extent by heating, or by the use of polymerization catalysts which are known to accelerate the polymerization of vinyl-type compounds. Such catalysts are the organic peroxides (e. g. benzoyl peroxide, acetyl benzoyl, acetyl b'enzoyl peroxide, lauroyl peroxide, oleoyl peroxide, etc.), hydrogen peroxides, perborates (e. g. sodium and potassium perborates), and persulfates (e. g. sodium, potassium, and ammonium persulfates) Although elevated temperatures can advantageously be used, we can use temperatures varying from ordinary room temperature (20 25" C.) to approximately fill-65 C. Higher temperatures can be used,'however, the aboverange is usually adequate. The polymerization can also be carried out by the bead or emulsion method in which water or some other medium in which the monomers are insoluble is employed as a dispersing medium, with or without emulsifying agents. The polymerizations can also be performed by use of a solvent which dissolves the monomer, but not the polymer, which preclpitates from the. solution as it forms. Alter: natively, the diluent or. solvent,s-suchas benzene,

8 toluene, xylene, -'etc., can. be a solvent iforvthe polymer. The emulsion method; of polymerization has been found to be particularly advantageous,.since the rate of polymerization and form of polyrner can be easily controlled.

The esters prepared in accordance with our invention can either be homopolymerized or copolymerized with. another unsaturatedcompound containing a group. The following examples will illustrate the manner in which we prepare polymers from our a-acyloxyacrylic esters.

EXAMPLE X.-HOMOPOLYMER OF ETHYL a-ACETOXYACRYLATE The ester prepared in Example V above was polymerized by heating at 50 C. in the presence of 0.1% benzoyl peroxide as a polymerization catalyst. A clear, hard mass of polymer was obtained which had the following analysis:

Calculated Found A niolecularly equivalent amount of C ljll a-propionoxyacrylate can be substituted in the above example, a hard, tough homopolymer being obtained.

EXAMPLE XI.HOMOPOLYMER 0F E'IHYL lat-BENZOXYACRYLATE .173 gms. of, ethyl u-benzoxyacrylate were homopolymerized. by heating with 0.1% benzoyl peroxide at 50 C. A clear, hard resin having the following analysis was formed:

Calculated Found C 64. 9O 64. 42 H 5. 40 5. 37

A molecularly equivalent amount of n-butyl a-benzoxyacrylate can be substituted in the above example, a hard polymer suitable for molding being obtained.

EXAMPLE XII.HOMOPOLYMER OF METHYL ot-ACETOXYACRYLATE 5'gms..of methyl a-acetoxyacrylate and 0.1% of'benzoyl peroxide were heated on 'a water bath for 20 hours at 50 C. "A clear, colorless, hard homopolymer was obtained.

A molecularly equivalent amount of benzyl a-acetoxyacrylate can be substituted in the above example to advantage.

EXAMPLE XIII.,I-IoMoPoLYMER.-or ETHYL oc-ACETOXYACRYLATE '9 fresh methanol, and then dried at 50 C. in vacuo. Analysis was as follows:

Calculated Found EXAMPLE XIv.-HOMOPOLYMER OF ETHYL d-ACETOXYACRYLATE 15.8 gms. of ethyl a-acetoxyacrylate and 0.08 gm. of benzoyl peroxide (no solvent) were placed in a sealed tube under an atmosphere of nitrogen .and the tube placed in a constant temperature bath maintained at 50 C. 1 0.). After heating for 15 hours, a hard, clear resin had formed in the tube.

EXAMPLE XV.-EMULSION HOMOPOLYMERIZATION F ETHYL a-ACETOXYACRYLATE a-acetoxyacrylate was then added, and the jar tumbled end over end in a 50 C. constant temperature water bathat about 16 R. P. M. After 20 hours the product was filtered, and the resulting beads were thoroughly washed with dis- ,tilled water, and then dried at 50 C. in vacuo.

A yield of 16.6 gms. of clear, hard beads of homopolymer was obtained.

EXAMPLE XVI-EMULSION HOMOPOLYMERIZATION or ETHYL a-ACETOXYACRYLATE 200 gms. of ethyl u-acetoxyacrylate, 50 gms. of

.dibutyl phthalate, and 0.5 gm. of benzoyl peroxide were shaken until the catalyst was in solution. This solution was then added to a solution of 1.2 gms. of gum arabic in 600 cc. of distilled water which was contained in a quart fruit jar with a clear rubber seal. The jar was then placed in a constant temperature bath maintained at 50 C. (11 C.) and tumbled end over end for 20 hours at 16 R. P. M. The resulting hard, white beads were washed by decantation until the wash waters were clear. After a final washing the product was dried in an enamel tray at room temperature. The yield of polymer was 195.5 gms.

EXAMPLE XVIL-l-IOMOPOLYMERIZATION OF ETHYL a-BUTYROXYACRYLATE 40 gms. of ethyl a-butyroxyacrylate and 0.1 gm. of benzoyl peroxide were mixed, and then shaken until a clear solution was formed. This solution was added with stirring to a solution of 0.24 gm. of gum arabic in 120 gms. of distilled water contained in a magnesium citrate bottle. The bottle was placed in a constant temperature bath maintained at 50 C. and tumbled end over end for 20 hours at 16 R. P. M. The resulting hard, white beads were washed by decantation until the wash water was clear, and then dried first at room temperature, followed by a 20-hour drying in a vacuum oven. The yield was 37 .5 gms.

EXAMPLE XVIII.--HoMoPoLYMERIzA'rIoN or ISOBUTYL a-ACETOXYACRYLATE 40 gms. of isobutyl -acetoxyacrylate and 0.1

gm. of benzoyl peroxide were mixed and shaken. until a clear solution was obtained. This solution was then poured into a solution of 0.24 gm.

1 of gum arabic in 120 gms. of distilled water conunder an atmosphere of tained at 50 C. (i? C.) and tumbled end ever end for 20 hours at 16 R. P. M. The resulting hard, white beads were washed by decantation until the wash waters were clear, then dried first at room temperature, followed by a 20-hour drying in a vacuum oven. A yield of 38 gms. of polymer was obtained.

EXAMPLE XIX.-HOMOPOLYMERIZATION 0F METHYL oL-ACETOXYACRYLATE A solution of gms. of methyl a-acetoxyacrylate, 85 cc. L l-dioxane, and 0.22 gm. of benzoyl peroxide were, placed in a sealed glass tube under an atmosphere of nitrogen, and the tube placed in a constant temperature water bath maintained at 50 C. After 20 hours 9. viscous, non-flowing mass had formed which was dispersed in hot dioxane. This was then poured into a large excess of methanol, and the white precipitate washed with first methanol. After drying at 55 C. a yield of 65 gms. of the polymer was obtained.

EXMPLE XX.-HoMOPoLYMERIzA'rIoN OF ErrrYL a-BUTYROXYACRYLAIE 5 gms. of ethyl a-butyroxyacrylate and 0.5 gm. of benzoyl peroxide were shaken until a clear solution was formed. After heating the solution for 20 hours on a constant temperature bath maintained at 50 C., a clear, colorless, hard homopolymer was obtained.

EXAMPLE XXI.-HOMOPOLYMERIZATION OF ISOBUTYL oc-ACETOXYACRYLA'IE A solution of 5 gms. of isobutyl a-acetoxyacrylate and 0.5 gm. of benzoyl peroxide was placed in a constant temperature bath maintained at 50 C. and polymerized by heating for 20 hours. A clear, colorless, hard polymer was obtained which exhibited excellent molding properties.

EXAMPLE XXII.--HOMOPOLYMERIZATION OF N-BUTYL a-ACETOXYACRYLATE 5 gms. of n-butyl c-acetoxyacrylate and 0.5 gm. of benzoyl peroxide were mixed and shaken until clear solution was obtained. The solution was then placed in a constant temperature bath maintained at 50 C. and polymerized by heating for 20 hours. The resulting homopolymer was clear, colorless, and hard, and was found to be suitable for molding.

EXAMPLE XXIII.COPOLYMER or E'IHYL oz-BUTYR- OXYACRYLATE AND ETHYL oL-ACETOXYACRYLATE 9.3 gms. of ethyl a-butyroxyacrylate, 7.9 gms. of ethyl a-acetoxyacrylate, and 0.086 gm. of benzoyl peroxide were placed in a sealed glass tube nitrogen, and the tube placed in a constant temperature water bath maintained at 50 C. After 16 hours a hard, clear polymer was obtained.

EXAMPLE XXIV.-COPOLYMER 0E ISOBUTYL cz-ACET- OXYACRYLATE AND ETHYL oL-ACETOXYACRYLATE 9.3 gms. of isobutyl u-acetoxyacrylate, 7.9 gms.

of ethyl a-acetoxyorylate, and 0.086 gm. of hen- 50 C. After 16 hours a clear, colorless, hard resin was formed.

EXAMPLE XXV.-Co1=oLYMER 0F METHYL oc-METH- ACRYLATE AND ETHYL oc-ACETOXYACRYLATE 15.8 gms. of ethyl a-acetoxyacrylate, 10.0 gms.

. of methyl a-meth'acrylate, and 0.13 gm. of ben- .zoyl peroxide were placed in a sealed glass tube i1 under anatmosphere of nitrogen and the tube placed'in a constant temperature water bath maintained at 50 C. After three days a clear, hard resin was formed, which was dissolved in acetone. excess of methanol, the resulting precipitate redissolved in acetone, and the resulting solution poured into hot water. After drying the reprecipitated product at50 C.,-a yield of 24 gms. of

copolymer was obtained. The acetyl content of the copolymer was found by distillation to be 14.7%, representing a molar ratio of methyl amethacrylate to ethyl a-acetoxyacrylate of approximately 1.5: l in the copolymer.

EXAMPLE XXVI.COPOLYMER OF STYRENE AND ETHYL oc-ACETOXYACRYLATE tained. The ethoxyl (C2I-I5O--) content of the copolymer was found tobe 16.6%,- indicating a molar ratio ofstyrene to the ethyl a-acetoxyacrylate of approximately 1.1:1 in thecopolymer.

By substituting a molecularly equivalent amount of p-methylstyrene in the above example, a copolymer suitable for molding canbe obtained.

EXAMPLE XXV'II.--COPOLYMER F METHYL zit-METH- ACRYLATE AND ETHYL u-BUTYROXYACRYLATE- 9.3 gms. of ethyl m-butyroxyacrylate, 5.0 gms. of me hyl e-methacrylate, and 0.072 gm. of benzoyl peroxide were sealed together in a glass ampoule under. an atmosphere of nitrogen. The

. ampoule was then placed in a constant temperature bath maintained at50 C. After 3 days a clear, colorless, hard resin was formed.

By substituting a molecularly equivalent amount of n-butyl a-methacrylate or diisopropyl fumarate in the above example, othervaluable copolymers can be prepared.

EXAMPLE XXVIII.-COPOLYMER OF STYRENE AND ETHYL oa-BUTYROXYACRYLATE 9.3 jgrns. of ethyl a-butyroxyacrylate, 5.2 gms. of styrene, and 0.072 gm; of benzoyl peroxide ,were sealed together in a glass tube under an atmosphere of nitrogen. The tube was placed in a constant temperature bath maintained at 50 C. After '7 days a clear, colorless, and hard resin was formed.

ExAMrLsXXlXr-CoPoLYt/miz or STYRENE AND ISOBUTYL oL-ACETOXYACRYLATE 93 gms. of isobutyl aacetoxyacrylata'fiz gms.

., of Styrene, and 0.072gm. ofbenzoyl peroxide wereplaoed in a: sealed glass tube under an atmosphere of nitrogen. The tube was placed, in a constant temperature bath maintained at '55) C. After 7 days a clear, colorless, and hard resin had formed.

EXAMPLE X XX.- -COPOLYME'R or METHYL DL'METH- Acarrere AND rsosU'rYL ca-ACETOXYACRYLATE 9.3 gins. of isobutyl c-aceto'xyacrylate', 5.0 gms. of methylcemethacrylate and 0.972 gm. of benzoyl peroxide were sealed together in a glass' am-- This solution was then poured into an 1 12 poule under i an atmosphere of. 1: nitrogen r. and placed in a C. bath-maintained at constant temperature. After 3 days a clear, colorless, and hard resin was formed.

By substituting a molecularly equivalent amount of methyl vinyl ketone, methyl isopropenyl ketone, or vinyl acetate in the above example, other copolymers suitable for molding can be obtained.

EXAMPLE XXXI.POLYMER or ETHYL a-ACETOXYACRYLATE A solution of 0.25 gm. of benzoyl peroxide in 250 cc. of ethyl a-acetoxyacrylate was poured into a glass cell, whose inside dimensions were 8" x 6 x 4", until the cell was almost full. The cell was then covered with a glass plate, and the cell set in a C. oven maintained at constant temperature. After 16 hours the monomer had polymerized to a solid, butheating was continued for an additional day. On. removal from the .cell there was obtained a clear, colorless plate of excell nt physical, properties.

Other unsaturated compounds. can be used to advantage in the above examples. For example, methyl acrylate, n-butyl acrylate, etc., are excellently suited for forming copolymers with the a-acryloxyacrylates of our invention.

We claim:

1. A process for preparing an ester ofan a-acyloxyacrylic acid which comprisesreactingan ester represented by the formula:

wherein R1 represents a member selected from the group consisting of an alkyl group having the formula CnH2n+l wherein .n is a positive integer from 1 to Land a mononuclear arallcyl group having '7 to 10 carbon atoms, and X is a halogen atom selected from the group consisting of chlorine and bromine atoms, with a member selected from the group consisting of anhydrides and acid halides of an acid represented by the formula:

R-COOI-I .rinating the formed methyl a-acetoXy-fl-halopropionate by heating with an organic tertiary amine.

3. A process for preparing an ester of an il-acyloxyacrylic acidwhich comprises dehydrohalogenating an ester represented by the formula:

wherein R representsa-member' selected fromthe groupconsisting of analkyl group having 1 to 3 carbon atoms, and an .aryl. group having 6 to '7 carbon atoms, R1 represents a member selected from the group consisting an alkyl group having "the formula CnH2n-i-l, wherein n is a positive intege'r from 1 to l, and a mononuclear aralkyl group having '7 to 10 carbon atoms, and X represents a halogen atom selectedrfrom the group consisting of chlorine and bromine atoms, by heating said ester with an organic tertiary amine;

'7. A process for preparing methyl a-acetoxyacrylate which comprises dehydrochlorinating methyl a-acetoxy-p-chlorpropionate by heating the said methyl a-acetoxy-c-chlorpropionate with an organic tertiary amine.

8. A process for preparing methyl a-acetoxyacrylate which comprises dehydrochlorinating methyl a-acetoxy-p-chlorpropionate by heating the said methyl a-acetoxy-p-chlorpropionate with 10 quinoline.

WILLIAM O. KENYON. CORNELIUS C. UNRUH. THOMAS T. M. LAAKSO.

No references cited.

Certificate of Correction March 7, 1950 Patent No. 2,499,393

WILLIAM O. KENYON ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 61, for the Word example read examples; column 5, line 24, for (13 mols) read (13+ mols) column 7, line 14, for cooler read cooled; column 13, lines 7 and 8, for a-chlorolactate read B-chlorolactate; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 4th day of July, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommissz'oner of Patents. 

1. A PROCESS FOR PREPARING AN ESTER OF AN A-ACYLOXYACRYLIC ACID WHICH COMPRISES REACTING AN ESTER REPRESENTED BY THE FORMULA: 